1. Field of the Invention
This invention relates to the use of alkyl sulfosuccinates based on alkoxylated fatty alcohols as collectors in the flotation of non-sulfidic ores.
2. Statement of Related Art
Flotation is a separation technique commonly used in the dressing of mineral crude ores for separating valuable minerals from the gangue. Non-sulfidic minerals in the context of the present invention are, for example, apatite, fluorite, scheelite and other salt-like minerals, cassiterite and other metal oxides, for example titanium and zirconium oxides, and also certain silicates and aluminosilicates. In general, the ore is first subjected to preliminary size-reduction, dry-ground or preferably wet-ground, and suspended in water. Collectors are then normally added to the ores, often in conjunction with frothers and, optionally, other auxiliary reagents, such as regulators, depressors (deactivators) and/or activators, in order to facilitate separation of the valuable minerals from the gangue constituents of the ore. After a certain contact time, air is blown into the suspension (flotation). A froth is thus produced at the surface of the suspension. The collector hydrophobicizes the surface of the minerals so that they adhere to the gas bubbles formed during the activation step, and are then stripped off in the form of a mineral-containing froth and further processed. The object of flotation is to recover the valuable mineral in as high a yield as possible while, at the same time, obtaining a high degree of enrichment.
Anionic and cationic surfactants are predominantly used as collectors in the flotation of non-sulfidic ores. These collectors are intended to be selectively absorbed to the surfaces of the valuable minerals in order to obtain a high enrichment level in the flotation concentrate. In addition, the collectors are intended to act to form a buoyant, but not too stable flotation froth.
Alkyl sulfosuccinates are frequently used in the flotation of non-sulfidic ores (W. v. Rybinski, M. J. Schwuger, "Aufbereitungstechnik", 26 (1985), page 632 and A. Doren, loc. cit.). In many cases, good flotation results can be obtained with collectors such as these. In some cases, however, known alkyl sulfosuccinates lead to undesirably intensive frothing.
U.S. Pat. No. 4,138,350 describes alkyl sulfosuccinates with an ethoxylated alkyl chain as flotation collectors. However, it has been found that the alkyl sulfosuccinates based on ethoxylated alcohols which are described in U.S. Pat. No. 4,138,350 do not always have favorable frothing properties for flotation or a good collector effect.